Magnetic recording media and, particularly, audio compact cassette tapes (hereinafter, referred to as cassette tapes) are made so as to have high performance year by year. Improvement of sensitivity and frequency characteristic, improvement of MOL and SOL and improvement of dynamic range by making noise low have been made. With respect to the position of the cassette tapes, development of tapes for normal position so as to be used in high position and, further, in metal position has occurred.
Hitherto, in audio cassette tapes for high position, chromium dioxide and Co coated or doped magnetic iron oxide were used as magnetic materials. Further, as layer construction, tapes having a monolayer or multilayer construction were used. With respect to tape characteristics for high position, tapes having a coercive force (Hc) of 560 to 680 oersteds and a residual magnetic flux density of 1400 to 1900 gauss were much studied.
In recent years, ferromagnetic metal powders having larger magnetic moments than the prior magnetic materials have been studied (for example, Japanese patent application (OPI) 64629/83). (The term "OPI" as used herein refers to a "published unexamined Japanese patent application".)
However, there are problems that the frequency characteristic balance in high position is not sufficient, output in a low band is inferior, a squareness ratio is small and demagnetization is large.